A fuel cell is an apparatus directly converting chemical energy of fuel and air into electricity and heat by an electrochemical reaction. The fuel cell, unlike an electric power generation technology in the related art adopting fuel combustion, steam generation, turbine driving, and generator driving processes, does not have a combustion process or a driving apparatus, and thus the fuel cell is a novel concept of electric power generation technology having high efficiency and not causing an environmental problem. This fuel cell has merits in that since air pollution materials such as Sox and NOx are hardly emitted and carbon dioxide is less produced, pollution-free electric power generation, low noise, and no vibration are attained.
Examples of the fuel cell include various kinds such as a phosphoric acid fuel cell (PAFC), an alkaline fuel cell (AFC), a polymer electrolyte fuel cell (PEMFC), a direct methanol fuel cell (DMFC), and a solid oxide fuel cell (SOFC), and among the fuel cells, the solid oxide fuel cell (SOFC) has high electric power generation efficiency because of a low overvoltage and a small irreversible loss based on low activation polarization. Further, since in addition to hydrogen, carbon or hydrocarbon-based fuel may be used, a width of fuel selection is wide, and since a reaction speed in an electrode is high, an expensive precious metal as an electrode catalyst is not required. Moreover, heat emitted to be concomitant with electric power generation has a very high temperature, and thus a utility value thereof is high. Heat generated in the solid oxide fuel cell may be used to reform fuel, and may be used as an energy source for industries or cooling in steam supply and power generation.
The solid oxide fuel cell may be classified into an anode support type, a cathode support type, an electrolyte support type, and the like according to a relative thickness of a support. The anode support type SOFC has a merit in that since electric conductivity of an anode is high, even though the anode support type SOFC becomes a thick support type, current resistance is not large.
Therefore, there is a demand for developing a technology for improving performance of an anode support type solid oxide fuel cell and durability of the fuel cell.